bug 2148: there was no way to remove a single header without wiping them all out, so add a remove_header configuration option to deal with single headers.
bug 2148: there was no way to remove a single header without wiping
them all out, so add a remove_header configuration option to deal with
single headers.


git-svn-id: d99324e817494df82bb0080d8e7ab74680731a10@5581 13f79535-47bb-0310-9956-ffa450edef68

apache/spamassassin,apache/spamassassin,apache/spamassassin,apache/spamassassin,apache/spamassassin